The treatment of colorectal cancer beyond surgical resection has shown relatively little progress over the years and it is thererfore imperative that well-designed clinical trials continue to test therapeutic hypotheses in a sequential fashion. The NYU Cancer Center considers clinical trials in colorectal cancer as one of its most relevant and urgent priorities. Within a broad range of clinical activities we seek to develop and integrate multiple facets of ongoing and on-line experimental and epidemilologic research and seek to participate in GITSG trials as part of the Project "Thereapy of Patients with Early Stage Colon and Rectal Cancer". The predicatable frequency and pattern of recurrences in this disease may be used to design therapeutic trials in patients at moderately high risk, which have a good chance of rapidly answering therapeutic questions. The new resources which we will bring to the GITSG are detailed in the subsequent sections. Dr. Franco Muggia, will assume the responsibility of Principal Investigator. This will ensure the full participation of resources present within Medical Oncology and its liasion activities with other scientific disciplines. As co-investigator, the Chairman of Radiation Oncology, Dr. Joseph Newal, has similarly mad a major commitment to research on colorectal cancer. Additionally, first rate surgery and pathologic evaluation are probably the most important single determinants of therapeutic results and the availability of such surgical participation constitutes the principal strength of the proposal. For example, since nearly 50 percent of patients with colon cancer destined to recur do so in the liver; radiotherapy and/or chemotherapy directed specifically towards eradication of microscopic hapatic metastases is an area of active research interest. In rectal cancer, radiologic and radiotherapeutic techniques which have improved over the years now allow combined regimens with chemotherapy at acceptable morbidity and are yielding encouraging results.